The liquid dispensing valve apparatus of the present invention is adapted for use in livestock oiling and insecticide dispensing apparatus of the general type shown in U.S. Pat. Nos. 2,988,050 and 2,988,051.
One of the problems with such dispensing valve apparatus is to maintain operability under extremely difficult operating conditions without continuous attention of the farmer or rancher. The apparatus must dispense liquid oil and insecticide freely when cattle are present yet close off the dispensing passages completely when the cattle leave. The dispensing apparatus is mounted in the open so as to be subject to extremes of year-round heat, cold, snow, rain, ice, dryness, wind, etc. In addition, the materials dispensed are often relatively corrosive and have a tendency to clog flow passages by themselves or in combination with dirt, blood, animal hair, etc. While all of the foregoing factors can cause clogging of dispensing passages and dispensing valve apparatus, I have discovered that a primary reason for clogging of dispensing valves involves malfunction of the valve apparatus due to reaction between the dispensing valve parts and the materials being dispensed. In particular, I have discovered that conventional O-ring seals, which have heretofore been employed in connection with oil and insecticide dispensing valve apparatus, tend to absorb and react with the oil and the insecticide so as to become inoperable by reason of swelling, disintegration and degradation. In this connection, I have determined that certain types of material are far better suited for use in oil and insecticide dispensing apparatus for cattle. Another problem is providing a dispensing valve which will dispense enough oil and insecticide without dispensing too much. Also the dispensing valve must be securely mounted so as not to be dislodged by the cattle. Other problems solved by the present invention are difficulties of assembly and mounting of the valve apparatus, unreliable sealing of the valve housing relative to surrounding suppport member, and lack of durability in use.
The afore-recited problems have been overcome in the present invention by providing: ( 1) a one-piece valve housing member of molded nylon material frictionally sealingly mounted by only an interference fit in a mounting bore in a support plate with a thin edge convexly rounded outlet passage portion extending beyond the support plate, ( 2) a one-piece valve plunger member of molded nylon material, and (3) an O-ring seal between the plunger member and the housing member made from flurocarbon material which is relatively inert and impermeable with respect to the oil and insecticide dispensed and mounted in a new and improved manner, as more fully described hereinafter by reference to the accompanying drawing.